WO2001092679A1

WO2001092679A1 - Device for raise boring

Info

Publication number: WO2001092679A1
Application number: PCT/SE2001/001105
Authority: WO
Inventors: Christer Gustafsson
Original assignee: Uniroc Ab
Priority date: 2000-05-29
Filing date: 2001-05-18
Publication date: 2001-12-06
Also published as: SE0001991D0; AU6090701A; SE0001991L

Abstract

Device for raise boring comprising a rotation device (1), a drill string (2) and a reaming head (5). The reaming head (5) comprises a connection part (6) with a spring biased first body (7) which is displaceable between two end positions. The tube (3) being closest to the reaming head (5) in the drill string (2) comprises a second body (9) about which a connection means (10) is displaceable between a first position (fig 3) where the connection means (10) is unturnable relative to the second body (9) and a second position (fig 4) where the connection means (10) is turnable relative to the second body (9). Through this a safety device is achieved which prevents the reaming head (5) from falling if the joint between the reaming head (5) and the drill string (2) should break.

Description

Device for raise boring

The present invention relates to a device for raise boring. More particularly the invention relates to such a device provided with a device for catching a reaming head if the joint between a connection part of the reaming head and the first tube should break.

A problem that sometimes arises in raise boring is that the joint between the reaming head and the drill string can break. If that occurs the reaming head falls down and can be damaged or damage equipment being present under the shaft. It can also happen that the reaming head gets stuck i the shaft so that it becomes difficult to get it out.

In a previously known solution of the problem of avoiding damages that can arise if the joint between the connection part of the reaming head and the first tube should break one has used a wire through the connection part and the tube and fastened the wire. This method has the drawback that it has to be performed manually. It can thus not be used if personell neither can nor may be in the vicinity of the borehole.

The present invention, which is defined in the subsequent claim, aims at achieving a device for raise boring which makes it possible to connect the connection part of the reaming head with the first tube of the drill string and connection of a safety device for joint breakage without manual work.

An embodiment of the invention is described below with reference to the accompanying drawings in which fig 1 shows a section through a rock formation with a device for raise boring. Fig 2 shows a connection part and a tube being parts of the device for raise boring according to fig 1 before these parts have been connected to each other. Fig 3 shows the parts connected to each other. Fig 4 shows the parts when the joint between the connection part and the tube has broken.

The device for raise boring shown in fig 1 works in a rock formation 13, in the shown example between a gallery 17 and a lower level 18. In raise boring a borehole 14 is first drilled after which the drill bit is changed to a reaming head 5 provided with a connection part 6 which is connected with a drill string 2 comprising a number of tubes 3. During the reaming the drill string 2 is drawn upwards by means of hydraulic cylinders 15 and rotated by means of a rotation device 1. During boring the rollers 19 are pressed against the rock which is crushed. The joint between the connection part 6 and the first tube 3 in the drill string 2 is situated inside the marked area 16 which is closer shown in figs 2-4. The connection part 6 is in the shown example provided with a thread 20 for connection with a thread 21 on tube 3 in drill string 2. The tube 3 is at its other end provided with a thread 26 for connection with the next tube in the drill string 2. In the connection part 6 a first body 7 is movable between two end positions defined by the recess 24 in the first body 7 and the pin 25 in the connection part 6. The first body 7 is displaced towards the position shown in fig 2 by a spring 8, i.e. in a direction away from the reaming head 5. The first body 7 is in the shown example a rod but could also be made in another way, e.g. a wire. The first body 7 is provided with means 11, in the shown example a thread. The shown tube 3 comprises a second body 9 which is connected with the tube 3 by means of a suitably formed fastening 27. The second body 9 is in the shown example a rod but can also be made in another way, e.g. a wire. A connection means 10 is displaceable about the second body 9. The second body 9 is provided with two flanges 28,29 and splines 22. The connection means 10 is provided with splines 23 and means 12 in form of a thread for connection with the thread 11 on the first body 7. In fig 3 the connection part 6 and the tube 3 are shown connected. Furthermore, the first body 7 and the connection means 10 are connected. In fig 4 thread 20 has broken. The connection part 6 and thus the reaming head 5 are then hanging in the drill string 2 through the first body 7 and the second body 9. The connection means 10 is displaceable between a first position, fig 3, where the connection means 10 cannot be turned relative to the second body 9 because the splines 22,23 are in engagement with each other and a second position, fig 4, where the connection means 10 can be turned relative to the second body 9 because the splines 22,23 are not in engagement with each other.

The device shown in the drawings works in the following way. First the borehole 14 is bored to the lower level 18. Then the drill bit is dismounted and the reaming head 5 is positioned under the borehole 14. This procedure is not described since it does not form part of the invention. This position is shown in fig 2. Then the drill string 2 is rotated and fed toward the reaming head 5. The first body 7 then moves the connection means 10 to the position shown in figs 2 and 3. The thread 11 is then screwed into the thread 12 because the connection means 10 is unturnable relative to the tube 3 due to cooperation between the splines 22,23 in this position. The thread 20 is also screwed into the thread 21. This position is shown in fig 3. After this it is bored with the reaming head 5 with the assistance of the rotation device 1 and the hydraulic cylinders 15. If for instance the thread 20 should break during the boring as shown in fig 4 the reaming head 5 is catched by the first body 7 through cooperation between the pin 25 and the recess 24. The first body 7 is still connected with the connection means 10. The connection means in this position rests with its splines 23 on the flange 29 on the second body 9. In this position the connection means 10 is turnable relative to the second body 9. Through this it is avoided that torque released from the drill string 2 when the thread 20 or the thread 21 breakes destroys the first body 7 or the second body 9.

Claims

Claim:

1. Device for raise boring comprising a rotation device (1), a drill string (2) connected to the rotation device (1) and comprising several tubes (3) connectable with each other, and a reaming head (5) connectable with the drill string (2) and provided with a connection part (6), c h a r a c t e r i z e d in that the connection part (6) comprises a first body (7) movable between two end positions and which is biased by a spring (8) in a direction away from the reaming head (5), that the tube (3) arranged closest to the reaming head comprises a second body (9), that a connection means (10) is displaceably arranged about the second body (9) between a first position (fig 3) where the connection means (10) is unturnable relative to the second body (9) and a second position where the connection means (10) is turnable relative to the second body (9) and that the first body (7) and the connection means (10) comprise means (11,12) for connection with each other.